Many modern vehicles include on-board electronic control systems that manage and record operation of the vehicle's various subsystems. On-board electronic control systems may include or otherwise support on-board diagnostic (OBD) services that enable vehicle owners and repair technicians to access diagnostic information or other forms of operational information from the control system. As one example, on-board electronic control systems may be accessed via a data interface in the form of a physical wired data link connector or data port, such as ALDL, OBD-I, OBD-1.5, OBD-II, or other suitable data interface.